University Sound Cobreflex IIB
A reflex horn that folds two air columns into one grey ABS bell. The patent paperwork that tested it says the response never came out flat.
Overview
The Cobreflex IIB is a folded sectoral horn built by University Sound, the brand that ended up under the EVI Audio umbrella. It carries item number ER1045797 in the catalog listings that still reference it. The patent literature calls it, in full, a "Cobraflex II B folded sectoral horn, from University Sound (IIB)," which is the dry, exact phrasing of an engineer writing a test report instead of a sales sheet.
It is a reflex-type horn: an exponentially flared design that folds the horn path back on itself to get usable loading out of a package that stays reasonably compact. A straight exponential horn long enough to load down to a useful cutoff is a physically enormous object. Fold it, and the mouth and throat fit into a manageable footprint without giving up the acoustic behavior. The IIB sits in a family. The patent that tested it also names a Cobreflex III folded sectoral horn, and the two are distinct models that should not be conflated.
One thing up front. The IIB shows up in patent US4982436A as a comparison loudspeaker, and the testers were not flattering. The frequency response of the IIB "was not yielding a flat response signal." The Cobreflex III, tested alongside it, was judged better but still not flat. That is not a marketing claim and it is not an owner's complaint. It is an engineer's measurement note, and it is the most specific thing anyone has documented about how this horn behaved.
Key Features
Folded Sectoral Geometry
The defining feature is the fold. A sectoral horn flares in two planes, and the IIB folds that flare into a single assembly instead of letting it run straight out to a distant mouth. Patent documentation describes the IIB as a folded sectoral horn, and a current marketplace listing describes the same family of hardware as a "Sectoral Horn Exponentially Flared." The two descriptions are consistent. This horn is built to be mounted in real rooms, on real walls, at heights where a straight horn would be impractical to hang and impossible to aim.
Aluminum Construction
At least one listing for a University Sound Cobreflex horn describes it as an aluminum sectoral horn, exponentially flared. That listing is not confirmed to be the IIB specifically, so the material claim is a family-level description and not a verified IIB specification. What can be said without hedging is that the Cobreflex IIB is constructed from a high-impact acrylonitrile butadiene styrene (ABS) with an ultraviolet inhibiting grey paint finish. Whether every IIB left the factory in aluminum is not something the available documentation settles.
Built as a Test Reference
The IIB was also used as a reference loudspeaker in acoustic polar-plot testing for patent US4982436A. Its behavior was measured against a known standard, and the measurement survived in the public record. For a piece of PA hardware that was never going to get a magazine review, that is an unusual amount of documentation, and it says the response was lumpy.
Historical Context
Production years for the IIB are not documented in the available sources, and the original price is not recorded either. What is documented is the IIB's appearance in patent US4982436A, where it served as the second loudspeaker tested - a "Cobraflex II B folded sectoral horn, from University Sound (IIB)" - and where the patent explicitly notes that its frequency response was not flat. The same patent tested a Cobraflex III, judged better but still not flat, and the patent's own methodology note states that each ring in the polar plots represents 6 dB of SPL.
That is the entire historical record in these sources. No launch date, no catalog year, no lineage narrative.
Collectibility & Value
The market for the IIB is thin and the data is thinner. A single current listing asks $350 for a "University Sound Cobreflex IIB Sectoral Horn Exponentially Flared -New," located in the Glendale area of Los Angeles. A separate Los Angeles listing asks $450 for a "University Sound Cobreflex Aluminum Sectoral Horn Exponentially Flared," but that listing is not confirmed to be the IIB, so it should not be read as a comparable sale. There is also an eBay listing for a pair of "University Sound CobreFlex 2 Horn Speaker Pair W/ T-30 Driver Unit." The model naming there does not match the IIB cleanly enough to draw any conclusion from it. No price was captured for that listing.
No common failures, no maintenance notes, and no spare-parts availability turned up in the research. Anyone buying one of these is buying it on the strength of the horn itself, not on the strength of a documented restoration path. The $350 asking price is a single data point, not a market — treat it as an opening number, not a valuation.
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